TV’s newest Jersey girl is tall, refined and — heavens! — undeniably British. Janet Montgomery, star of CBS’ legal drama “Made in Jersey,” seems the most unlikely choice to play a junior associate at a snooty New York law firm who schleps across the Hudson each day but refuses to let go of her blue-collar roots, producer Kevin Falls admits.

“Understandably, networks can be a bit concerned: ‘Is that accent going to bleed through?’” he says. “But Janet quickly made us forget that she was English.”

Montgomery, 26, had only been in America for two years when she landed the part of Martina Garretti, who pronounces the name of the Garden State as “New Joisey.”

In the premiere, Garretti helped a college student beat a murder rap by relying on her knowledge of hairstyling products. When she won her first case, she celebrated by getting a tattoo — a tiny purple star — near her pelvis.

“Becoming the Jersey girl and learning the accent, that was the fun part for me,” says Montgomery, 26. “I still get things wrong. Unless you grew up in New Jersey you are going to get things wrong.”

In person, she speaks with a British accent and says she doesn’t really need to stay in character on set. “I have always had an ear for accents that I can switch it on or switch it off,” she says. “In the beginning, maybe more so. But now I am so in Martina. I spend more time being Martina than I do being Janet.”

Like Garretti, Montgomery came from a traditional working-class family. She was raised in Bournemouth, England, where both of her parents worked for the postal service. The family lived in a two-bedroom flat and Montgomery shared a bedroom with a her six siblings until she was 10 years old.

To help support the family, Montgomery landed her first job at 13. She earned 2.85 pounds an hour waiting tables at the Bournemouth town cafe. She was three years young to be legally employed.

“I moved out at 16 and paid my own rent,” she says. “I worked at Pizza Hut in Bedford when I went to dance school.”

When a knee injury ended her scholarship, Montgomery turned to acting.

“There was a point where I couldn’t get an audition,” she remembers. So, at 23, Montgomery moved to LA and ultimately landed a 10-episode role on HBO’s “Entourage” as Jennie, the assistant to Eric (Kevin Connolly) at the talent agency where he worked.

“That was a real lifeline for me because I was really running out of money,” she admits. “I auditioned as an American, but we weren’t sure if I was going to play it English or American. I got to create this very sweet, smart female character on a male-dominated show where most of the women were in bikinis playing ping- pong.”

The actress doesn’t own a television, but has been boning up on iconic series such as “Ally McBeal” and “The Sopranos” through Netflix. She scored the “Made” role via a Skype audition while vacationing back in England. She prepared for the part by getting to know families in Clifton, NJ, where many “Sopranos” scenes were filmed. “It had lots of restaurants, which is how I imagined [New Jersey to be],” she says. “There was a school there that I said ‘I could imagine [Martina] going to there.’ And there is a really big Italian vibe there.’”

To complete her Garden State “research,” Montgomery hopes to attend her first Bruce Springsteen concert in coming weeks. The series’ 15 hour-a-day filming schedule has precluded her from attending last month’s show at MetLife Stadium.

“He is in Connecticut on the 25th of October, which is just before my birthday,” she says. “I am going to see if production will clear me for that evening. I am such a huge fan.”